[libav-tools] Fail to concatenate 2 videos

Damien Brémont damien.bremont at casadevelazquez.org
Wed Apr 22 19:29:23 CEST 2015


Hi,

I'm trying to concatenate 2 different video files.

The first is a title image i generate with those commands:
/# I generate a 2 sec mute video
avconv -y -loop 1 -r 27.75 -i blank.png -vcodec h264 -t 00:00:02 -an 
output.avi
# And I had a blank sound
avconv -y -ar 44000 -b 320 -ac 2 -f s16le -i /dev/zero -i output.avi 
-shortest -c:v copy -c:a mp3 -b:a 320k output-2.avi/

So finnally I have this file (avconv -i)
/Stream #0.0: Video: h264 (High), yuv420p, 1920x1080, 27.75 fps, 27.75 
tbr, 27.75 tbn, 55.50 tbc
Stream #0.1: Audio: mp3, 44100 Hz, stereo, s16p, 320 kb/s/

The second file is generated from a digital recorder. Here is all the 
detail on that file. I don't want to transform this file because, I will 
have to process many files
/Stream #0.0: Video: h264 (High), yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], 
27.75 fps, 30 tbr, 30 tbn, 60 tbc
Stream #0.1: Audio: mp3, 44100 Hz, stereo, s16p, 320 kb/s/

So it's not exactly the same setting. Tbr, tbn and tbc differ...

When I try to concatenate with :
/avconv -y -i "concat:output-2.avi|Recorder_2_Apr20_19-55-28.avi" -c 
copy final.avi/

But I have some audio troubles.
When avconv is processing I have this error message :
/Non-monotonous DTS in output stream 0:0; previous: 392, current: 361; 
changing to 393. This may result in incorrect timestamps in the output file.
Non-monotonous DTS in output stream 0:1; previous: 467, current: 424; 
changing to 468. This may result in incorrect timestamps in the output file.
Non-monotonous DTS in output stream 0:1; previous: 468, current: 425; 
changing to 469. This may result in incorrect timestamps in the output 
file./

And the sound is destroyed and unsynchronised

So the question is how to adjust Tbr, tbn and tbc parameters on the 
first video?

I didn't find any option to H264 codec to change those parameters

Do you have an idea to solve this issue?

Thanks in advance for your help
Best
Damien
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